It was not immediately clear where Basil Rajapaksa, who also holds US citizenship, was trying to go.

He resigned as finance minister in early April as street protests surged against shortages of fuel, food and other necessities, and quit his seat in parliament in June.

His elder brother Gotabaya Rajapaksa will resign as president on Wednesday to make way for a unity government, after thousands of protesters stormed the presidential palace on Saturday demanding their removal.

The president has not been seen in public since Friday and his whereabouts are unclear.

The prime minister, Ranil Wickremesinghe, announced he would resign on Saturday hours before his home in Colombo was set on fire by protesters.

The Sri Lanka Immigration and Emigration Officers Association said its members declined to serve Basil Rajapaksa
at the VIP departure lounge of the Colombo airport.

"Given the unrest in Sri Lanka, immigration officials are under tremendous pressure to not allow top-level people to leave the country," KAS Kanugala, chairman of the association, told Reuters.

"We are concerned for our security. So until this issue is resolved, the immigration officials working at the VIP lounge
decided to withdraw their services."

Pictures of Basil Rajapaksa at the lounge were carried by local media and widely shared on social media, with some people expressing anger at his attempts to leave the country.

A senior official in the ruling party said on condition of anonymity that Basil Rajapaksa was still in the country.

The Rajapaksa family, including former prime minister Mahinda Rajapaksa, has dominated the politics of the country of 22 million for years and most Sri Lankans have blamed them for their current misery.

The tourism-dependent economy was hammered badly by the pandemic and a fall in remittances from overseas Sri Lankans, while a ban on chemical fertilisers damaged farm output. The ban was later reversed.

The Rajapaksas implemented populist tax cuts in 2019 that affected government finances while shrinking foreign reserves curtailed imports of fuel, food and medicines.

Petrol has been severely rationed, and long lines have formed in front of shops selling cooking gas. Headline inflation
hit 54.6% last month, and the central bank has warned that it could rise to 70% in the coming months.

Sky News correspondent Nicole Johnston, in Colombo, said people had been queuing for fuel for three days.

"People also don't enough food or medicine," she said.

Protesters have vowed to stay put in the official residences of the president and the prime minister until they quit.

There have been reports of queues of up to two kilometres of people waiting to go inside the presidential palace.

Read more:
President's palace becomes people's palace
What has lead to Sri Lanka's emergency?

Mr Wickremesinghe did not move into his official residence, Temple Trees, after taking office in May, and was away when protesters set fire to his home.

Sri Lanka's parliament will elect a new president on 20 July, paving the way for an all-party government.

The main opposition party Samagi Jana Balawegaya has announced it will nominate its leader, Sajith Premadasa, for the position.